This disclosure relates to the field of electric toothbrushes and, particularly, removable brush heads attachable to an electric toothbrush handle.
Many types of electric toothbrushes use high-speed vibrations or oscillations from a motor disposed within the toothbrush handle to drive a separately-attachable (and replaceable) brush head. In order to operate the electric toothbrush, the construction of the brush head requires that it be tightly coupled to the drive shaft of the toothbrush handle so as to withstand the high-speed vibrations during operation of the toothbrush. Many existing products, therefore, utilize metal and/or springs inside the brush head to facilitate a tight coupling to the drive shaft of the toothbrush handle and withstand the vibrational forces present during operation of the toothbrush, which limits the vibration felt by the user, as well as the noise caused by such vibration. However, use of metal, springs, gears, and/or linkages within the brush head may increase the complexity and/or cost of manufacturing the brush head. Therefore, it is desirable to make a toothbrush head with little to no use of metal, springs, gears, and/or linkages, yet still be capable of withstanding high-speed vibrations present during operation of the toothbrush.
Replacement brush heads that do not include metallic components, springs, gears, and/or complex linkages have previously been introduced in an effort to simplify and/or reduce manufacturing costs of the brush heads. For example, U.S. Pat. No. 9,439,741 discloses a replacement brush head for an electric toothbrush utilizing a drive construction having a unitary, non-metallic brush shaft configured to drive a bristle carrier into rotational and/or oscillatory motion. The brush shaft relies upon a thin eccentric extension laterally offset from the longitudinal axis of the brush shaft to interact with a V-shaped opening on the bristle carrier in order to translate the oscillatory motion imparted by the toothbrush motor into rotational and/or oscillatory movement of the bristle carrier. However, as the eccentric extension is offset from the axis of the brush shaft, the high torque experienced by the eccentric extension when interacting with the V-shaped opening of the bristle carrier may lead to excessive wear on the eccentric extension and/or bristle carrier, high vibration and noise, and, in some cases, failure of the eccentric extension portion of the brush shaft. Additionally, as the brush shaft and bristle carrier may each be unitarily formed of a non-metallic material (e.g., plastic, polyester, etc.), the wear and/or failure rates may be even more prominent.
This patent document describes an apparatus that may address at least some of the issues described above and/or other issues.